Physico-chemical properties and microbial ecology of the Lagos Lagoon, Nigeria

Abstract

TheLagoscity is an urbanized commercial nerve center ofNigeriawith complex ecological environment.  The Lagos Lagoon is a typicalNigeriacoastal aquatic environment of salt and brackish water with complex microbial diversity.  The physical and chemical properties of surface water affected the distribution pattern of microbes.  The temperature and pH are relatively stable.  The averages of pH values were pH 7.28 and pH 6.55 for February and June period of sampling respectively, while temperature average 31°C during this period.  The salinity and conductivity of the water were high during the month of February.  The chlorides content determined by Mohr titration method was within permissible level of 250mg/l specified by WHO.  The calcium content and suspended solid value were relatively high during the period of sampling.

      During the study, Agboyi creek shows the highest microbial count of 8.5 x 10³ CFU per 100ml to the lowest of1.5 x 10³ CFU per 100ml recorded for station 2 special.  The highest coliform count was observed in stations 2 and Agboyi creek respectively with 7.1 x 10³ CFU per 100ml while other stations varied with low coliform counts.  In the sediment, high values up of3.3 x 10³ CFU per gram sediment samples was obtained.  Various microbial species encountered during the study and their respective percentage distributive occurrence in the Lagoon were bacillus spp. (31.21%); B. megaterium (16.7%), Micrococcus spp. (10,40), Klebsiella spp. (9.25), Enterobacter spp. (9.25), Escherichia coli (8.09), B. polymyxa (4.62), Veillonella spp. (2.89), Streptococcus spp. (1.73), Pseudomonas spp. (1.73), Proteus vulgaris (1.73), Aeromonas hydrohila subsp.  Anaerogenes (1.69), Bifidobacterium adolescentis (o.57), and Moraxella bovis (0.57).  The study shows that, theLagos lagoon is largely inhibited by antibiotic resistant organisms and enteric bacteria which may have some health implications.